The introduction piece has to introduce your character, giving enough to allow other authors to write about them - but not enough that it becomes limiting. This is where I would request the most feedback to be, as I'm a new writer so both those lines tend to be a tad blurry. Also ways of removing wish fulfillment could be nice as I understand the trends around self inserts frown sincerely on that.
As ever grammatical errors, punctuation problems etc are *most* welcome.
Many thanks,
Keel

Okay, here we go. This fell to page 4 without any replies, so I’m giving it a quick read. I’ll comment on specifics for the first 10 errors I notice, then move on to a skim-read until I hit the end or I lose interest in continuing. Please note that I do not comment on every single thing that I think needs fixing, unless the piece is exceptionally good. Here are my thoughts:

Okay, so the start is… pretty hectic. I have no idea who the protagonist is, why there are terrorists involved, who the Vicar is (is the Vicar the protagonist?), or why the story begins with a guy waking up but suddenly gets captured and a bag put over his head? There's a lot for a reader to try to make sense of in the first enormous paragraph, and it's not the best way to start off a piece.

some kind by 2 men > write out all numbers less than 10. Two men.

a lot stronger than himself, who threw him into a room > how can he tell they're that much stronger? Guy's got a bag over his head and he's restrained, so he's kind of automatically at a disadvantage.

taking the bag off as they did so. It contained one thing he noticed immediately > phrasing makes it seems like the bag contains the thing

containing the word KEEL. His real name. > EHHHHH. For obvious author self-inserts, readers may have a knee-jerk negative reaction, especially if the character is pretty far removed from the totally normal, non-action-hero-y readers themselves. It's hard to identify with and want to root for someone that you have absolutely nothing in common with.

Panic spread through him. "Why wasn't he dead?", the more sensible, shrinking part of his brain called out to him > why wasn't who dead?

If he'd been rumbled, which he obviously had, why hadn't he been decapitated yet? > I have no idea what this means, so it doesn't really do much for me as a reader. What is rumbling and how is it related to decapitation?

A realization struck him, the sensible part of his brain swelling with pride. > two quick mentions of sensible brain part is a little repetitive and overdramatic.

He hadn't been found out, he'd been pulled out by someone powerful enough to waltz into a skyscraper, with a restrained man, without any security checks whatsoever. > how does the guy know he's in a skyscraper? How is that relevant to the current scenario?

The vicar, wearing the uniform > where did this vicar come from? He's never mentioned previously. Only the table with the paper was introduced earlier in the paragraph.

Overall… I'll be honest. This looks very sloppy. Maybe start off by using a word processor/writing assistance program (Grammarly is something I recommend often, since I've heard good things about it) to fix up the basic things like lack of spaces after punctuation and sentence fragments like "The curl of disgust creeping onto the General’s face."

Right now, you've got kind of a hard to suspend disbelief story happening; the Foundation typically would be smart enough to restrict recruitment to willing participants. MTFs are supposed to be the best of the best, and if this guy is just randomly transferred and he seems to be pitching a fit over it, that makes the scenario look questionable and the Foundation rather incompetent.

I say get your character and their backstory checked and polished up in the Ideas and Brainstorming forum before you try adding more to this. You can ask for help with putting together a more believable backstory, and developing the guy's personality and quirks into something more interesting than the kind of formulaic video game tacticool drama king premise you currently have.